Remember the summer of 2001? It was a media feeding frenzy on the highly appropriate topic of sharks: shark attacks in US coastal waters were the third-most reported news item. But the media was calling attention to a “trend” of increasing shark attacks that didn’t actually exist. 2001 was actually a lower than average year for shark attacks. Warren Mayer explains the similarities between 2001’s “Summer of the Shark” and 2012’s heat wave:
This summer we have been absolutely bombarded with stories about the summer heat wave in the United States. The constant drumbeat of this coverage is being jumped on by many as evidence of catastrophic man-made global warming.
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Trend, you say? Doesn’t a 100-year high temperature in and of itself imply warming? Certainly not. I believe this will prove to be an exaggeration, but for a moment let’s assume that this heat wave has created the hottest June in 100 years for half the Continental US. That seems pretty extreme, right? But the Continental US is about 2.5% of the world’s land mass. Just by math, in a stochastic system with a stable mean, a land area of this size somewhere should have a 100-year high month about five times a year! One data point about one small patch of the Earth having a hot month tells us nothing about trends.
[. . .]
What the Summer of the Shark needed, and what this summer’s US heatwave needs, is a little context. Specifically, if we are going to talk about supposed “trends”, then we should look at the data series in question over time. So let’s do so.
